Making articles of argillaceous materials.



R. 1). MERSHON. MAKING ARTICLES OP ARGILLAOEOUS' MATEMALE APPLICATION FILED AU G. 28, 1908. 1,034,81 5.

Patented Aug. 6, 1912.

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his arrow m1 UNITED STATES PATENT orrroE.

RALPH D. MERSHON, OF NEW YORK, N. Y.

MAKING ARTICLES F ARGILLACEOUS MATERIALS.

Specification of Letters Patent.

Application filed August 28, 1908. Serial No. 450,760.

Patented Aug. 6,1912.

To all whom it may concern: a

Be it known that I, RALPH D. Mnnsnou,

a citizen of the United States, residing at,

New York, in the county and State of New York, have invented certain new and useful. Improvements in Making Articles of Argillaceous Materials, of which the following is a specification.

' In themanufacture of porcelain articles of' the surface portions produces strains considerable difli'ciilt-y has been experienced in preventing the formation of cracks while the article is drying. Great care must be exercised tosee thatthe drying proceeds at a uniformrate throughout the entire body, since if the evaporation from the surface is faster than the capillary conduction of moisture from the interior the greater shrinkage "which-thefllow tensile strength of the clay 1551either direction is unable to withstand. Buteven when such care is used as to make the drying approximate uniformity; throughout the article, it frequently happens that cracking still results, particularly in the case of an article of considerable size or one having thick walls. So far as I am aware, no adequate explanation v of such cracking has been ofiered, nor have prior efforts to overcome the drawback been attended with material success. After careful study'of the matter, and considerable experimenting, I have reached what I believe to be the true explanation of the vdifficulty, and practical tests of the present invention, which is based on my discovery, have been productive of results which leave practically noroom for doubt as to the correctness of my theory.

can no longer flow, and, therefore,"results in the minimum of internal stress, it any.

In carry-ing out my invention in the preferredmanner I employ a mold'which (and this f'Irregard as one 'of the most important features ofth e invention) will permit the free passageof water-through its walls in ct retain the clay in the .desiredishape; uch a mold may be made in various ways. For example, I have produced excellent results with a mold made of wire gauze, such as is used for window screens, lined with paper. Thus for making a porcelain cylinder I provide a gauze cylinder of the necessary size, making the same large enough to allow for the unavoidable shrinkage of the clay in dryin Several thicknesses of the gauze may be used,

to give the walls of the shell sufiicient stifl ness and strength. The cylinder is now lined with'tissue'paper, or even ordinary manila wrapping paper and is then @filled with dry porcelain body in finely divided or powdered condition, well shaken and pressed down to make the material as dense as maybe. The mold thus filled is now immersed in water until the clay is thoroughly saturated to a plastic condition, after which the gauze cylinder with its contents is removed for drying. The drying proceeds rapidly, because of the fact that the article of argillaceous material is surrounded only by paper and netting, but without the appearance of cracks. If desired, the outer gauze shell may be removed when the drying has proceeded to the point where the clay is stiff enough to stand without distortion. The scheme thus outlined may also be employed for making more complicated shapes, by forming the outer shell of netting in the'shape desired; but, in general, if this is carried too far there may be more or less trouble for the reason that before the clay has dried sufficiently to permit removal of the supporting shell there will. have beenconsiderable shrinkage; and as the shell cannot shrink with the clay, crackin or breakage will result' I overcome this difliculty, however, by making the mold, or particular parts thereof, out of material which will keep pace with the clay in Such a mold, or the necessary parts thereof, can be made of powdered clay shrinkage.

lightly pressed into form and then covered with tissue paper or other suitable material,

which, while allowin thepassage of water, will prevent the ama gamation of the form or mold with the object being molded; or

a paper form filled with dry clay: For example, a hollow cylinder of argillaceous materials may be moldedas' 'follows: In algauze cylinder prepared as described above I place a cylinder of wood or other convenient and suitable material, wrapped with paper loosely enough 'to permit ultimate wi drawal of the wooden cylinder but leaving the paper wrapping in place. The annular space. thus provided in the gauze mold is now filled with powdered clay settled down to place. The wooden cylinder is then removed, the central space filled with dry powdered clay, and the whole soaked in 'the simple and convenient apparatus illustrated herein. This apparatus is shown in vertical section in the accompanying drawing.

Referring now to the drawing, 1 indicates aforaminous mold of suitable form, inclosed in a vacuum chamber 2 connected with an air pump 3. The clay is contained in a chamber or receptacle 4 and is delivered into the mold, preferably by gravity, through a conduit 5 having a valve or gate 6. This clay receptacle is likewise connected with the air pump, as is also a chamber 7 containing water. Inthe pipes connecting the various chambers. with the air pump are valves 8, 9., 1O, 11, by which communication between the various parts of the apparatus can be controlled, as will be readily understood. v

-Valves 6,8, 11, being closed and 9, 10 open,

the. air pump is operated, therebyexhausting the air from the water in chamber D, in

order? to: have the water itself free from all.

dissolved or entrapped' air. After suche haus'tion-,-a'i r may be readmitted to the cy-l if;

inder 7, without fear of any appreciable amount "of air being taken up, as water will taketnp air very slowly unless agitated.

Valve 8 being now, open and valve 9closed,

' air, is exhausted from chambers 2- and 4, thus time,'the particles of clay, as they fall, will be robbed of such air as clings to them, with the result that the clay is deposited in the removing as much of the air from the clay material as can be removed from it ina body. .The air pump being kept in operation, thegate 6 is opened and the powdered clay allowed to fall slowly into the mold l. Inasmuch as the air pump isworkingall the gauze cylinder 1 practically free of all air. This having been accomplished, valves 6, 8, 9 and 10 are elosed and water under atmospheric pressure is admitted into the chamber 2 from chamber 7& through valve 11, thus surrounding the gauze cyllnder and its con tents with water and, since a vacuum exists between the particles of clay, bringing a pressure of about fifteen pounds per squareinch upon the clay, tending to make the same more compact. At the same time by capillary action, the water works in between the particles of clay, rendering it plastic. If desired, the pressure can be increased by pumping water into the chamber 2'. Also, if desired, hot water can be used instead of cold, in order to obtain the greater plasticity which hot water produces in some clays. Insuch case, the water can be sup plied from a steam boiler and will, therefore, enter the chamber 2 under a pressure equal to theboiler pressure. If this scheme resorted to, however, care must be taken to cool down the clay cylinder or other article in chamber 2 before the pressure therein is relieved; otherwise the clay article may be ruptured by the formation of internal steam. The mold with its contents is now removed for dryingas before, care being of course taken to have the drying'proceedat a rate as nearlyas possible uniform throughout the mass. f

In the above description, reference has been made-only to the use of dry clay for filling the mold; that is, putting the mate-' rial into the mold dry and afterward wetting it. The clay may, however, be wet first,

using suflicient water to make the mass I liquid enough to be poured. However, I

consider the dry way much more advantageous than the other ;-first, because a consid-p erable excess of wateris required to make.

pouring of the mixture possible, which excesshas to be eventually. gottenrid'of; sec end, because 'it is easier, in the case of the vacuum process, to remove the air from the dry clay than from the emulsion of the same.

.- .A-s previously stated, one of the most important features of I the. invention is the mold, which'permits the free passage of water in either direction without allowing escape of the clay. Such a mold may be made of wire gauze, perforated sheet metal,

or other. foraminous material of suit-able character, lined with-paper as described, or cloth, or, in general, any material which will permit water tdpassfreely through it but retain the fine'cl'ay until it is sufiiciently wet to keep it from escaping through the foraminous outer .shell. Or, instead of using a lining of paper, cloth, etc., the shell may be dipped in a solution of boiled starch. This would leave the apertures in the shell covered with a film of starch, which would keep the powdered clay from falling through; and yet when the mold is immersed in water the-starch would allow the water to pass freely through it and would gots which are aftenrard finished by turning in a lat'he,'as is customary; since it is extremely ditlieult. with the prior methods, to form these ingots without danger of their cracking in the drying.

What I claim i:

l. lhe herein-described method of making articles of argillaeeoua materials for subsequent firing, \vhieh vonSiStS in depositing a loose mass of dry mlrerulent material in a gauze mold lined with paper or fabric-adapted to permit the passage of water in either direction through its walls but prevent the escape of the powdered material; immersing the mold, containing the loose uncompaeted material, inwater until the material is saturated to a plastic condition; and removing the gauze mold and its contents for dnving.

2. The herein described method of making articles of argillaceous materials for subsequent tiring which consists in depositing a loose mass of dry pulverulent material in a mold and around a suitable filler smeh as wood, said mold adapted to permit the paamge of water in either direction but preventing the escape of powdered material; immersing the meld and core containing the material, in Water until the material is saturated to a plastic condition: removing the tiller and filling the space le t; thereby, by a material or core having the sa me or approximately the same shrinkage and drying the article and core.

RALPH I). HERSUON. W it uesses:

S. S. Domini, Tnonus J Dramas. 

